Study On In-situ Modification Of Hydrogenated Nitrile Rubber With Metal Salts Of Unsaturated Carboxylic Acid

In this thesis,domestic hydrogenated nitrile rubber(HNBR)was selected as the matrix material,the modification process and effect of in-situ modification technology on HNBR were studied,and the reinforcement effect of in-situ modification technology combined with carbon black(silica)reinforcement system and ternary comprehensive reinforcement system was studied.The concrete content is divided into the following three parts:The first part: HNBR reinforced by zinc acrylate(ZDA)in situ formed from zinc oxide(ZnO)and acrylic acid(AA).The influence of ZDA on the structure of HNBR was analyzed by FTIR and SEM.The effects of the molar ratio of ZnO/AA,the theoretical amount of ZDA in situ formation and the amount of DCP on the modification of HNBR were studied systematically.Through the analysis of FTIR and SEM,the results showed that in the process of high temperature vulcanization,In-situ ZDA was polymerized by DCP radical,and self polymerization and graft polymerization occurred.The ionic bond formed between rubber and covalent bond formed "ionic covalent bonding",which significantly improved the mechanical properties of HNBR.The shore A hardness and 100% constant elongation stress of HNBR increased with the increase of ZnO/AA molar ratio,ZDA theoretical in-situ production and DCP content,the elongation at break of rubber compound decreased constantly,and the tensile strength increased primarily,decreased slowly after the peak.The second part: the effects of different metal oxides on the modification of HNBR by in-situ form of acrylate from MgO,Cao,ZnO and acrylic acid were studied.FTIR was used to analyze the structure of HNBR modified by three kinds of in-situ synthesized acrylates;the distribution of acrylate in HNBR was observed by SEM;the total crosslinking density,covalent crosslinking density and ionic crosslinking density of pure HNBR and three kinds of modified HNBR were characterized by the method of equilibrium swelling,and their comprehensive mechanical properties were compared.Results display that the ionic bond formed by in-situ acrylate in HNBR and the covalent bond initiated by peroxide cooperate to form "ionic covalent bonding" which greatly improves the performance of HNBR;The difference of compatibility between different metal oxides and HNBR affects the content and dispersion of salts in the matrix,resulting in the ionic crosslinking density was different,which affected the mechanical properties of HNBR vulcanizates;Among the three kinds of in-situ synthesized acrylates,Zn DA has the best modification effect on HNBR,with uniform dispersion in the matrix and good compatibility,the ionic crosslinking density and total crosslinking density of HNBR are the best degree and the mechanical properties are the best;Mg DA is the second;and Ca DA is the worst.The third part: Firstly,the in-situ modification technology(ZnO and AA in-situ formed ZDA)combined with carbon black(silica)reinforcement system was used to comprehensively strengthen the rubber.The effects of the combination of the two reinforcement systems on the curing process,crosslinking density,oil resistance and mechanical properties before and after thermal oxidative aging of HNBR were studied,so as to study the comprehensive reinforcement effect of the three reinforcement systems.The results are as follows: the curing speed,torque and curve flatness of carbon black and silica reinforcement system are greatly improved by in-situ modification technology;Under the condition that the amount of filler remains unchanged at 30 phr,with the increase of theoretical ZDA content in filler,the crosslinking density increases,and the thermal oxidative aging resistance and oil resistance also improve.For mechanical properties,the properties of vulcanizates reinforced by in-situ modification technology combined with carbon black(silica)reinforcement system were also better than those reinforced by pure carbon black(silica)reinforcement system.And on this basis,the tensile strength of the ternary comprehensive reinforcement system rubber is as high as 31.5 Mpa,which has a significant industrial application value.